This invention relates to a warning system for refrigeration equipment which indicates when such equipment requires corrective maintenance to prevent continuance of an operational deficiency or malfunction until the refrigeration equipment becomes inoperable. More particularly, the warning system of the invention involves an electrical circuit connected in series with the electric motor which drives the refrigerant compressor of the refrigeration equipment.
Refrigeration equipment, which broadly includes freezers, coolers, refrigerators and air conditioners, has been the subject of many proposed warning systems designed to call attention to various mechanical or electrical malfunctions of the equipment. However, these prior proposals have failed to gain wide commercial adoption because of their complexity and high cost.
For example, U.S. Pat. No. 2,475,069 to Wood discloses a warning device for a refrigerant system comprising a fluid pressure reponsive means connected between the evaporator and the compressor of the system. Wood's device requires both fluid and electrical connections and is itself subject to malfunction because it includes a bellows which is a potential source of leaking refrigerant.
U.S. Pat. No. 3,415,070 to Weum shows a refrigeration malfunction warning system that includes: a jacket surrounding a refrigerant liquid header connected to receive a small amount of refrigerant liquid from the end of the header, and an electrical temperature sensor associated with the jacket. This complex system also requires both fluid and electrical connections. Worse yet, the jacket of the proposed system as a practical matter could only be installed at the time the refrigeration system is built.
U.S. Pat. Nos. 2,826,044, 3,628,346 and 3,839,877 are illustrative of other warning systems for refrigeration equipment which are not simple and cannot be easily installed in existing refrigeration equipment.
Accordingly, a principal object of this invention is to provide a simple and easily installed warning system for refrigeration equipment to detect malfunctions.
Another important object is to provide such a warning system that avoids connection into the refrigerant fluid piping.
Still another object is to provide a warning system which is made up entirely of electrical components and is easily connected in series with the motor that drives the refrigerant compressor of the refrigeration equipment.
These and other objects and advantages of the invention will be evident from the description which follows.